Digital Commons Network^™

Nutation Control During Precession Of A Spin-Stabilized Spacecraft, Richard James Donner

Masters Theses

"The effects of precession thrust pulses and energy dissipation upon nutation of a spin-stabilized spacecraft are studied. Methods for controlling nutation during a precession maneuver are proposed and examined. In particular, a precession modulation control law is developed which uses precession thrust pulses to control nutation. Digital simulations show that precession control with separate nutation control is the fastest precessing system; however, the precession modulation method is only fractionally slower while not requiring a separate nutation control system"--Abstract, page ii.

Interior Noise In Military Helicopters, Charles E. Perez Jr.

Masters Theses

"The Temporary Threshold Shift (TTS) or temporary hearing loss caused by excessive interior noise in military helicopters results in a critical degradation of the acoustically unprotected infantryman's ability to detect the existence or the approach of the enemy by hearing under combat conditions. The overall problem of noise reduction in helicopters consists of: (1) identifying the various noise sources, and (2) employing appropriate noise control techniques. Identification of the source is accomplished by the frequency correlation of 1/10-octave band analysis of the interior sound levels measured within the helicopter cabin with near-field sound generated by the sound sources. Reduction of …

Multispectral Analysis Of Erts Imagery By Color Enhancement, John F. Peters

Masters Theses

"The Earth Resources Technology Satellite (ERTS) program has supplied the scientist with high resolution multispectral imagery of a large portion or the earth. Photographic and electronic methods of image enhancement are not universally available to those who might profit from such endeavors.

Diazo products were found to be satisfactory for creation of false color enhancement of ERTS multispectral data. The purpose of the enhancement was to make the Diazochrome composite comparable to more sophisticated methods for the purpose of interpretation. The basis of the enhancement was the standard false color infrared composite, with negative and positive Diazochrome masks to enhance …

Driver-Vehicle-Roadway Interaction Model, Mark E. Jaeger

Masters Theses

"A non-trivial simulation model has been developed which combines driver and vehicle dynamics with the roadway into one system. The model was successfully simulated on a portion of an existing roadway with the dynamic response and performance of the simulator being subjectively realistic. By implementing the idea of the interaction of variables, a much more detailed and representative response is obtained as compared to previous models based solely upon a single-factor-effect approach. By analyzing a simulated vehicle's velocity and trajectory, it is felt that an increase in driver "look ahead" distance or a decrease in vehicle velocity tends to improve …

Inertial Navigation Performance Improvement Realized By The Technique Of Interrupted Alignment, Ralph E. Herndon

Masters Theses

"Present on-aircraft ground alignment gyro bias methods can basically be categorized as (1) periodic maintenance performed by the ground crew, (2) pre-flight calibration requiring a two-position gyro compass alignment or (3) optimal filter estimation of the north gyro bias error.

This thesis discussion presents an interrupted alignment method that allows adequate level axes gyro bias correction without the restrictions associated with a conventional two-position gyrocompass alignment (i.e., a minimum time for bias calibration on a steady aircraft). The interrupted alignment technique allows the pilot to select the navigate mode at any point during gyrocompass and reselect the align mode at …

Design And Construction Of An Electronic Pressure Altimeter For An Atmospheric Data Acquisition System, Larry Wayne Berkbigler

Masters Theses

"This thesis describes the design, construction, and application of an altimeter which was developed as part of the data acquisition system of a small aircraft used to study atmospheric conditions. The altimeter provides a digital readout and interfaces with analog and digital recorders. It can also provide an audio indication when a predetermined altitude is reached. The altimeter is powered by 12 volts dc, has resolution to 10 feet, and a maximum altitude of 15,000 feet. Its maximum theoretical error is ±78 feet ±0.77% of true altitude, which is an error of ±194 feet at 15,000 feet.

Since the unit …

Characterization Of A Mexican Halloysitic Clay And Behavior In Dry Pressing, Jesus L. Derat

Masters Theses

"A Mexican clay, intended to be used as refractory raw material, was identified. Problems encountered in the characterization of halloysitic clays are discussed and emphasis is made on the use of the electron microscope (scanning or transmission type) as a definite evidence of the existence of halloysite due to its unique morphology within the kaolinite group of clay minerals.

Beneficiation of this particular clay was carried out on a small scale hydrocyclone equipment and the results are discussed.

In an attempt to increase the green density in dry pressing of this halloysitic clay, mixtures with grog were prepared using different …

The Contribution Of Phonon-Induced Tunneling To Donor Esr Spectral Narrowing In Semiconductors, David Lawrence Meier

Masters Theses

"The narrowing of donor electron spin resonance spectra with increasing donor concentration N_D and increasing temperature T has been observed in semiconductors in the past. One proposed explanation for this phenomenon has been narrowing due to electron motion caused by phonon-induced tunneling (hopping) between donor sites. According to the Anderson narrowing theory, the line width of the narrowed line can be expressed in terms of the average square spread of the non-narrowed spectrum, < H²>_ave, and the average frequency of electron motion, ω_n. Previous work has been done on narrowing by hopping, but rigorous expressions for ω …

Liquid-Liquid Extraction With First Order Reaction : A Mathematical Simulation, Alan Wayne Smith

Masters Theses

"Models for mass transfer to droplets based on film theory with first order chemical reaction are proposed and compared with experimental data. The experimental extraction data is available from the work by Andoe (1968). The physical system used was benzene as a continuous phase and water as a dispersed phase with 2-chloro-2- methyl propane the solute diffusing into and reacting in the droplet. This system had a high interfacial tension (31.0 dynes/cm) and droplet Reynolds numbers ranging from 600 to 1345.

The predicted results of this work are in the form of the dimensionless total mass transferred to the droplet …

Numerical Calculation Of The Currents In Bent Wire Antennas, Min Ho Kang

Masters Theses

"The current distribution for bent dipole antennas is numerically calculated by using a digital computer. A delta-gap at the center is assumed for the drive. Several different bend-angles are considered including the cases of the straight wire and the inverted-L. The total length of the wire considered is λ/2 while the ratio of the bent portion over the vertical portion is varied. The method of solution is based on Mei's integral equation and the method of moments. The use of Mei's integral equation eliminates the need for the application of the boundary condition at the point of bending. For …

Model Correction For The Formation Of Amorphous Silicon By Ion Implantation, John Robert Dennis

Masters Theses

"ESR has been used to study the formation of an amorphous layer in silicon by ion implantation. The room temperature implants were done at 20 keV with low dose rates. The critical dose was determined as a function of ion mass for six different ion species. Our experimental heavy ion results agree with those found by other ESR investigators at higher energy, but are not the same for light ions. However, our light and heavy ion results agree with electron microscope measurements for low energy implants. An energy-independent model for the formation of amorphous silicon by ion implantation has …

Marshall Properties Of Asphaltic Concrete Containing Glass-Rich Fractions, James Joseph Schneider

Masters Theses

"The use of crushed waste glass as an aggregate in asphaltic concrete has been suggested as a means for re-using glass separated from municipal refuse. Laboratory studies and field installations have generally utilized clean glass obtained by hand sorting bottles from the other refuse and crushing them to produce a desired gradation. For this type of asphalt to be economical though, the glass fraction must be separated mechanically. For mechanically separated materials, the glass-rich fraction also contains such items as metal, bone, rubber and other non-glass materials.

The objective of the study was to determine the effects upon Marshall properties …

Digital Fault Calculations Of Large Systems Using Matrix Language And Generalized Equations, Saeed Abdel-Halim Khalifa

Masters Theses

"A new short circuit program has been developed for a large system. Several features have been provided to simplify handling of the system data. Various study cases are performed, efficiently, within the available computer memory. A master data bank is established from bus, feeder and transformer data. They can be modified internally to simulate various system configurations. Matrix formation is accomplished using a new sorting method and the IBM/360 Matrix Language MATLAN. A generalized set of ii ·equations have been developed and applied to calculate four types of faults.

The program consists of two phases of operations. In phase-1, input …

An Investigation Into The Degree Of Correlation Between Air Flow Rates, Bacteria In The Air And Post-Operative Infections In Hospitals, Carl Eugene Intag

Masters Theses

"Post-operative infections are a recognized problem in the medical and hospital professions. Annual costs and deaths due to infections in the U.S.A. have been estimated at $8-$9 billion and 10,000 lives respectively. The air lS one potential path in transporting contaminants that may cause an infection. Yet, the degree of influence airborne contaminants have in causing infections is a topic of much debate. As a result of the need for more information in this area, this investigation was undertaken to determine the degree of correlation between post-operative infection rates, bacteria in the air, and air flow rates.

Data for the …

Approximate Normal Mode Method To Determine The Response Of Certain Nondiagonalizabel Vibratory Systems, Jayaram Seshadri

Masters Theses

"An approximate normal mode method is developed which permits certain normally nondiagonalizable, nonconservative systems to be solved by superposition of uncoupled coordinates.

An approximate solution for a nonproportionally damped, multi-degree of freedom system is obtained by using a perturbation technique. The system is then reduced to a proportionally damped system by means of a modification to the damping factor so that the effect of the off-diagonal terms of the modal damping matrix is included. This modification produces a damping matrix that can be diagonalized by the normal mode technique. An approximate criterion is used for the determination of the modified …

Adsorption Of Water On Gold, Jean-Marc Louis Deschanel

Masters Theses

"Water adsorption isotherms on gold films were measured with a quartz crystal microbalance. Two gold films were studied: a "dirty" gold film contaminated by approximately one monolayer of carbon, and a "clean" gold film prepared by evaporating gold from a heated tungsten wire under high vacuum.

Water was found to chemisorb on both films according to a Freundlich type adsorption isotherm. Isosteric heats of adsorption were computed from the isotherm data. On the "clean" gold surface the isosteric heat showed a logarithmic decrease with increasing water coverage. The highest measured value for the heat of adsorption was 35 kcal mole …

A Study Of The Ability Of Surface Active Materials To Increase The Evaporation Rates Of Small, Freely Falling Water Drops, David Alan Sierawski

Masters Theses

"The evaporation rate at 30°C of water droplets partially covered by surface active materials (SAM) were determined. While two of the SAM were studied at a single dew point depression (ΔT_DP), seven others were examined over a range of ΔT_DP values. It was found, by comparison with pure water drops under identical conditions, that SAM increases the evaporation rate as compared to the rate of an uncontaminated drop. The lack of effect of the hydrophobic chain length and the possible effect of the hydrophilic group on this phenomenon are discussed. The explanation proposed is that at 30°C …

Attitude Scaling As A Public Involvement Tool In The Lower Mississippi River Region Comprehensive Study, William A. Lee

Masters Theses

"The planner is under considerable pressure to involve the public in water resource planning. The public, however, often lacks sufficient knowledge to offer useful comments or suggestions. The use of a Likert Type Attitude Scale in the public involvement effort of the Lower Mississippi Region Comprehensive Study demonstrates the usefulness of attitude scaling techniques in obtaining public input to the planning process. The measurement of an individual's attitude, or his thoughts, feelings and disposition to act toward some aspect of his environment with some degree of consistency, gives an indication of the goals and objectives toward which a plan acceptable …

Relative Volatility In The System 1-Butene - N-Butane, Steven Lewis Walker

Masters Theses

"An apparatus suitable for the rapid collection of P-x data at constant T is described. Isothermal P-x data at 40, 70, 100, 130, and 160 degrees Fahrenheit at the extremes of the composition range for the 1-butene - n-butane system are presented as a demonstration of the suitability of the device for its intended purpose. Limiting values of the relative volatility for the binary are presented. The relative volatilities were calculated using limiting forms of the general coexistence equation which are given in the literature. Several recommendations are given for improvements of the equipment and experimental technique"--Abstract, page ii.

Managerial Performance Appraisal, Benildus Wai-Young Lau

Masters Theses

"Questionnaire surveys were sent out to two hundred medium-sized companies in industry. The study is an attempt to find the main cause for the unsatisfactory results in most appraisal programs and to make recommendations concerning the implementation of an effective performance appraisal program. Human factors play an utmost important role in the success of the entire appraisal program. An atmosphere of mutual understanding and trust should be established between the well trained supervisor and his subordinate so that the rapport between them can be brought to the highest possible level. Performance appraisal should be considered as an integral part of …

A Comparison Of Three Urban Hydrology Models, Richard F. Astrack

Masters Theses

"Three models, the British Road Research Laboratory Hydrograph Method, the Hydrocomp Simulation Program, and the HEC-1 Flood Hydrograph Package, are applied to the Boneyard Creek basin. Comparing the ability of these models to reproduce the observed peak discharge, time of the peak, and the first runoff volume determines the accuracy of these models"--Abstract, page iii.

A Formal Description Of The Nova-800 Computer In Computer Design Language, Ronald Lee Engelbrecht

Masters Theses

"This paper presents a formal description of the operation of the NOVA 800 in Computer Design Language (CDL). For simplicity, the description does not include specific input/output devices, the multiply/divide option, or data channel operations. The description is intended to be used as a supplement in a basic course in computer organization, and an example of its use is included"--Abstract, page ii.

On The Complex Index Of Refraction Of Bulk Materials, Carol Jeanne Warren

Masters Theses

"As a part of the investigation of classical reflectance, it is determined that the hemispherical reflectance for a material with a particular pair of optical constants can be approximated by computing the angular reflectance at sixty degrees, using Fresnel's generalized reflectance formulas.

Reflection methods for the purpose of determining the optical constants of a variety of materials are discussed. The unpolarized reflectance versus angle of incidence technique is used for determination of the optical constants of bulk solids. Restrictions on the simultaneous solution of the Fresnel equations are determined and a computer program is developed to compute values necessary to …

The Design And Calibration Of A Vibrating Sample Magnetometer, Donald Dwight Hoffman

Masters Theses

"The design and calibration of a vibrating sample magnetometer is described. The sample motion was in the direction of the external magnetic field which was produced by a superconducting solenoid. The maximum external magnetic field was 70 kilogauss. Sample temperature could be varied from 77°K to 1000°K with a vacuum jacketed furnace. The maximum temperature was obtained with approximately 27 watts. The instrument was calibrated to 1% with a spherical nickel sample"--Abstract, page ii.

Monte Carlo Simulation Of Confidence Intervals For Reliability, Kathryn Palisch Berkbigler

Masters Theses

"A computer program which computes fiducial confidence intervals for reliability by Monte Carlo simulation has been written. The program has the capability of computing these intervals for general systems of series, parallel, and mixed series and parallel subsystems which have failure time distributions which are either exponential, Weibull, gamma, normal, or lognormal.

Comparison of the simulation technique with a Bayesian technique for computing confidence intervals in the case of a series of exponentially distributed components shows that the two methods agree quite well when a fiducial prior distribution for reliability is used in the Bayesian technique. A uniform prior distribution …

The Humanistic Aspect Of The Women's Liberation And Other Movements, John L. Longman

Masters Theses

No abstract provided.

The Effects Of Two Periods Of Light Deprivation On Bar Pressing In Rats, Edward R. Lyon

Masters Theses

No abstract provided.

A Study Of Personal Naming Customs In Medieval Poitou, Eleanor Louise Krawutschke

Masters Theses

No abstract provided.

Imitation: Some Theoretical Issues, Charles Richard Spates

Masters Theses

No abstract provided.

The Identification Of Potential Predictors Of Collegiate Success Of Black Students Enrolled In A Program For Disadvantaged Minorities, As Measured By Six Separate Success Criteria, Kerry Alan Bunker

Masters Theses

No abstract provided.